The notion of something "New" truly comes to shine in its Newness exactly at these opportune moments of discovery wherein we find ourselves at a loss of words, incapable, it seems to us, of properly describing what lies now present before us. But if that thing which we call "new" is to be genuinely "new", that is new in the most proper sense of the term, then it must come from without. In wandering further towards the edge of our linguistic horizon, only that which was not already expected and anticipated can count as new. Upon climbing a mountain, what lies beyond is sure to be "new" in some sense of the term, but still, more likely than not, what lies on the other side of the mountain will still be something which can be properly fitted into and described using our pre-existing conceptual schema.
I think our affective lives are among the best possible examples. Of the spectrum of the popularly known 34 thousand different emotions, you, like Headache, are having one - but which one is it? The emotion is at first there as "that emotion you do not know" - not unspoken, not ineffable, but unknown in the sense of something genuinely new which you must make an effort in order to be able better express. And with time, that expression comes. You describe it through analogy, through metaphor, and in doing so, you express it, not just superficially or to some inferior standard, but fully. I do feel like the smell of rain on a summer morning, or, to recall what I think is among the best poetry of Pink Floyd's The Wall: I do feel as cold a a razor blade, as tight as a tourniquet or as dry as a funeral drum. In saying these things, nothing is lost, all the pictures are complete, and, hopefully, we can understand each other through them. But this is the edge of language - and, I'd like to think, quite plausibly the origin of poetry.